Oxygen feeding refining method for molten iron and top-blow lance

Abstract

The invention discloses an oxygen feeding refining method for molten iron. At least a portion of the oxygen feed refining, provided is an oxygen-containing gas injection nozzle that passes through thehousing of a top-blowing lance, a control gas is discharged from the discharge port (3) toward the inside of the spray nozzle; an oxygen-containing gas, which is a main supply gas, is supplied from the inlet side of an injection nozzle and injected from the injection nozzle. The discharge port (3) is provided on the nozzle side surface of a region (1) where the cross-sectional area of the nozzleis the smallest in the axial direction of the nozzle or a region near the region, and is disposed such that at least a part of the discharge port exists in both spaces when the discharge port is divided into two parts by any plane passing through the central axis of the nozzle.

Description

technical field [0001] The present invention relates to an oxygen-supplied refining method of molten iron for performing oxygen-transport refining by blowing an oxygen-containing gas from a top-blowing lance to molten iron charged in a reaction vessel, and a top-blowing lance used for the oxygen-transmitting refining. Background technique [0002] In the oxidative refining of molten iron, from the viewpoint of improving the reaction efficiency, a practical oxygen supply method capable of simultaneously controlling the jet flow rate and the gas flow rate of the oxygen-containing gas injected from the top blowing lance on the molten iron bath surface has been sought. [0003] For example, in the decarburization refining of molten iron using a converter, from the viewpoint of improving the productivity of the converter, an operation to increase the flow rate of top blowing oxygen per unit time may be performed. However, in this case, if the flow velocity of the jet flow on the ...

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Problems solved by technology

[0016] In addition, in the method of Patent Document 2, the purpose is to separate the boundary layer of the gas flow from the wall surface of the nozzle at the enlarged tip of the Laval nozzle, and to alleviate the state of excessive expansion at low gas flow rates, but there is the following problem: when the gas supply pressure is higher than The flow rate cannot be effectively increased under the insufficient expansion condition of the appropriate expansion pressure determined by the opening ratio of the nozzle

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